This invention relates to electrical junction and outlet boxes. More particularly, it is concerned with electrical junction and outlet boxes of folded unitary construction.
Many electrical junction and outlet boxes presently in use are fabricated from a single sheet of metal which is drawn and shaped to the desired configuration. Drawn one-piece boxes have found favor in the industry because of their strength and structural integrity. One drawback of fabricating deep drawn boxes from plated sheet metal, however, is the formation of stress cracks in the surface plating and nonuniformity of side wall thickness which result from the drawing operation. Thus, for example, in the case of galvanized sheet steel commonly employed in the manufacture of wiring boxes, the box must be re-plated following the drawing step to forestall rusting. Drawn boxes are generally much more expensive to fabricate than boxes formed from separate side and bottom portions which are joined together by welding.
Electrical junction and outlet boxes fabricated of separate sidewall and bottom portions are known in the art. However, these multi-part boxes often lack the structural rigidity of one-piece boxes and frequently require elaborate interlocking or dovetailing tabs, slots and the like or welding to achieve strength. U.S. Pat. No. 3,877,601 to Evans et al., for example, describes a one-piece wiring box in which the walls and base are stamped from one piece of metal. The walls are folded up and then welded to provide the rigidity and strength in the finished box.